Multicomponet high speed cast irons has recently come to be used as work rolls for hot rolling of steels because it contains hard eutectic carbides and shows high resistance to wear. The mechanical strength and ductility are also required as roll materials. They are strongly dependent on the types, quantities and morphologies of eutectic carbides. In the present work the effects of alloying elements on the formation of eutectic carbides in white cast irons have been investigated.The cast irons with 2.0-2.5 mass%C,3-5 mass%V,2-8 mass%W,2-5 mass%Mo and 2-5 mass%W were melted using an induction furnace and cast into adiabatic molds with a riser. The solidified samples were microscopically observed and area fractions for carbides were evaluated. The chemical composition of each carbide is also analyzed by a scanning electron microscope with an energy dispersion analyzer. The regression relationships between volume fraction of carbides, Fv, and alloying elements are obtained from data. Obtained equations for MC carbide, M2C carbide and M7C3 carbide are Fv (MC)=1.20V-0.62, Fv (M2C)=0.63V+1.09Mo+0.77W-2.75 and Fv (M7C3)=3.18Cr-0.65Mo-7.04, respectively.